1. Field of the Invention
The present invention relates to a device for retaining casement windows, doors or the like, comprising firstly a bar adapted to be pivotally mounted on either a stationary portion or a movable portion of the window, door or the like, and secondly a catch member adapted to be mounted on the other one of the stationary or movable portions of the window, door or the like, and arranged to cooperate with the bar to releasably fix the stationary and the movable portions in a desired relative position, said bar having, at least on one side but preferably on two opposite sides, a longitudinal guide groove with a number of adjoining, transverse catch notches adapted to receive a catch heel arranged on at least one, but preferably on two opposite, facing walls defining a recess in the catch member for receiving the bar, said bar having at its outer end a stop which limits the movement of the catch member outwards along the guide groove in the bar.
2. Description of Background Art
A retaining device of this type is previously known by U.S. Pat. No. 3,807,780. When such a retaining device is used, for example, on an inwardly opening casement window, the catch member is mounted on the window sash, while the bar is fastened to the stationary window casing. From a closed position it is possible to open the window to a number of different limited opening angles by sliding the opposing heels in the catch member in their respective longitudinal grooves in the bar, and to lock it by swinging the arm so that the heels of the catch member snap into the desired catch notch on the bar. The bar and the catch member are adapted so that the bar can be completely released from the catch member in order to permit the window to be swung out to an entirely open position, for washing the window, for example. For this purpose, there is a notch between the respective guide groove and one lateral edge of the bar, with a little threshold being preferably arranged in this notch to prevent unintentional release of the bar from the catch member. Thus, in order to release the bar, it must be pressed with additional force away from the recess in the catch member receiving the bar, whereby the heels are forced apart by the threshold. The bar also has a slide-on ramp near the inner end of the guide groove, so that the catch member can be automatically coupled to the bar, when the window is being closed, by forcing the heels to separate and slide up on the ramp and snap into the guide groove in the bar.
This flexibility in at least one of the heeled legs of the catch member can, however, under certain conditions, cause an undesired release of the bar from the catch member; specifically if the latter is caused to be pressed quite hard against the outer end stop on the bar, e.g. if the window is opened violently. In this case the legs with the heels may be pressed apart so far by the bar end-stop that it can pass in its entirety through the recess in the catch member, thus freeing the bar from the catch member.